JPS644501Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a mold ejector plate quick return device for quickly returning the ejector plate to the ejector position during the mold closing process.

Prior Art In the injection molding process, molten resin is injected into a mold attached to a molding machine, molded and solidified, and then the mold is opened and the product is removed. At this time, the product stuck to the core side of the mold is ejected by ejector pins in conjunction with the mold opening operation of the molding machine.

The ejector pin that protrudes into the mold to eject the product is pushed back to its original shape by the return pin fixed to the ejector plate hitting the surface of the stationary mold plate in the next mold closing process. I am trying to return to the position.

However, for molds that use a slide core to mold products with undercuts or flanges, the ejector pin is removed before the slide block that moves the slide core returns to its original position during the mold closing process. It is necessary that the For this reason, this type of mold is generally provided with a quick return device for the ejector plate.

That is, as shown in FIGS. 4 and 5, molten resin is injected into a cavity consisting of a movable mold plate 1 and a fixed mold plate 2 attached to a molding machine (not shown) to form a product 3. After molding, open the mold and make product 3.
When taking out the product 3, the product 3 stuck to the core 4 side of the mold is ejected by the ejector pin 5 in conjunction with the mold opening operation of the molding machine, and the product 3 is taken out.

Specifically, when the movable mold plate 1 is lowered at the final stage of the mold opening process, the two ejector plates 6 that fix the ejector pin 5 are pushed relative to each other by the ejector rod 7 of the molding machine. As the ejector pin 5 moves forward, the tip of the ejector pin 5 ejects the product stuck to the core 4.

The protruding ejector pin 5 is pushed back downward in the figure when the return pin 14 fixed to the ejector plate 6 hits the surface of the stationary mold plate 2 during the mold closing process, and returns to its original position. The conventional general method was to

However, the example shown in FIGS. 4 and 5 is an example of a mold for molding a product having an undercut portion 9 on the outside, and the undercut portion 9 is formed by a slide core 10. This slide core 10 is formed as a part of a slide block 11 that slides on the surface of the movable mold plate 1, and when the angular pin 13 is fitted into the angular hole drilled in the slide block 11, the mold is rotated. It slides in the left and right directions in the diagram according to the opening and closing operations.

In the mold structure having the slide block 11 as described above, in the method of using the return pin 14, the ejector pin 5 is attached to the slide block 1.
There is a high risk of collision and damage to the ejector pin 5, so in the process of transitioning from the mold opening state shown in FIG. 4 to the mold closing state shown in FIG. It needs to be returned to its original position. Therefore, as described above, in this type of mold structure, a quick return device for the ejector plate 6 must be provided. In the conventional example shown in FIGS. 4 and 5, the spring 8
This fast reversal operation is performed.

That is, the receiving plate 15 and the ejector plate 6
A spring holding hole is formed in each of the holes, and a spring 8 is inserted between the two.
At the same time as the mold moves to the mold closing process, the ejector plate 6 is quickly returned by the elastic force of the spring 8.

In addition, in FIGS. 4 and 5, 16, 17
are the fixed side and movable side mounting plates, respectively, and 1
8 is a spacer block.

Problems to be Solved by the Invention However, when using the spring 8, there are the following problems.

(1) If the ejector pin 5 is galled, quick return becomes uncertain, and in that case, the ejector pin 5 does not return quickly and the slide block 12 and the ejector pin 5 collide and are damaged.

(2) The larger the ejection stroke, the greater the compression ratio of the spring 8, which may require a longer storage space, and even if a fairly strong spring 8 is used, the ejector plate 6 may return only halfway. Ru.

(3) The ejector plate 6 warps due to the elastic friction force of the spring 8, and the ejector pin 5 does not move smoothly.

(4) Accidents such as spring breakage or fatigue are likely to occur.

Further, as this type of quick reversing device, devices using cams and link mechanisms have been put into practical use, but these have had problems in that the mechanism has become complicated and the device has become large.

Purpose of the invention This invention was made to solve the above-mentioned problems. It is possible to quickly return the ejector plate even if the stroke is quite large, there is no risk of damage, and it is even easier. An object of the present invention is to provide a quick return device for a mold ejector plate, which has a simple mechanism, does not take up much space, and is easy to install.

Means for Solving the Problems Therefore, in order to achieve the above-mentioned objective, this invention has the following configuration as a gist.

First, a sleeve body is implanted on the ejector plate to which the ejector pin is attached and fixed, and a plurality of balls are loosely fitted in the circumference near the tip of the sleeve body. On the other hand, a pusher pin is implanted in the stationary mold plate portion of the mold that faces the sleeve body, and a bushing portion that serves as a guide for the sleeve body is further provided in the movable mold plate portion of the mold. The department includes
The ball is loosely fitted to the tip of the sleeve body, and has a large inner diameter portion in which the ball can move in the expansion direction within the sleeve body, and a small inner diameter portion in which the ball moves in the closing direction within the sleeve body. .

Function In the above-mentioned configuration, when the mold is opened, the sleeve body fits into the small inner diameter part of the bushing part, and the ball disposed near the tip of the sleeve body is pushed by the inner wall of the bushing part and radially Move in a direction toward the center. Then, in the first stage of the mold closing process, the pusher pin comes into contact with this ball and pushes the sleeve body itself, so that the ejector plate is returned to its original position, and the ejector pin is quickly returned. As the ejector plate returns, the sleeve body slides inside the bushing,
When the ball reaches the large inner diameter part of the bushing part, the ball opens along the radial direction to secure a guide path for the pusher pin, and the pusher pin fits into the sleeve body to clamp the mold. be.

Embodiments This invention will be explained below with reference to embodiments shown in FIGS. 1 to 3.

1 and 2 are sectional views showing the main parts of this invention, with FIG. 1 showing the mold in a closed state and FIG. 2 showing the mold in an open state.

The mold shown in FIGS. 1 and 2 has a fixed side mold part 20
and a movable mold part 21. The fixed side mold part 20 is
A fixed side mold plate 23 is fixed to a fixed side mounting plate 22, and a movable side mold part 21 has a receiving plate 26 and a movable side mold plate 27 fixed to a movable side mounting plate 24 via a spacer block 25. be.

The fixed mold part 20 is provided with an angular pin 43 that constitutes a sliding mechanism of a slide block 42 similar to that shown in FIGS. 4 and 5, and the movable mold part 21 is provided with a slide block 42. Furthermore, the ejector plate 32 is provided with an ejector pin 50 as in the conventional case. Further, 7 is a protruding rod of the molding machine. It is assumed that the product 3 to be molded is similar to that in the conventional example.

One pusher pin 28 is attached to the fixed side template 23.
is provided to protrude downward.

A pusher 29 is disposed on the movable template 27 so as to face the pusher pin 28 . As shown in FIG. 3, the upper end of this bush 29 has a through hole 29a for the pusher pin 28, the part following it has a small inner diameter part 29c, and the lower end has a large inner diameter part 29b, which will be described later. .

Further, a through hole 30 is formed in the receiving plate 26 directly below the bush 29. This through hole 30
A sleeve 33 is inserted into the ejector plates 31, 32 so as to be vertically movable integrally with the ejector plates 31, 32.

As shown in FIG. 3, this sleeve 33 has, for example, three or more small holes 35 formed at equal intervals around the circumference, into which balls 34 can be loosely fitted and positioned around an upper end opening 33c inserted into the bush 29. be. This small hole 35 has a shape that does not penetrate completely, but leaves a catch portion 33b on the inner circumferential surface so that the ball 34, which is made of steel, for example, does not fall into the sleeve hole 33a.

Effect of the embodiment Next, the operation of the above configuration will be explained.

At the end of one molding process and product ejection process, the mold is in an open state as shown in FIG. From this state, in order to perform the next molding process, the movable side mold part 21 is raised toward the fixed side mold part 20 as shown by the arrow in FIG.

That is, the pusher pin 28 relatively descends and passes through the through hole 29a of the bush 29 and the upper end opening 33c of the sleeve 33. However, since the sleeve 33 is located at the small inner diameter part of the bush 29, the balls 34 are in a closed state, and the lower end of the pusher pin 28 does not pass between the balls 34, 34, but pushes each opposing ball 34 and pushes the sleeve 33. 33 and ejector plates 31 and 32.

Then, when the tip of the sleeve 33 moves to the large inner diameter part of the bush 29 by being pushed by the pusher pin 28, the balls 34 move inside the small hole 35 and spread out from each other, and the passage inside the sleeve 33 widens. , the pusher pin 28 can pass through it loosely. In this state, the stripper plate 31 returns to its original position. Thus, fixed side template 2
7 and the movable mold plate 23 are in close contact with each other as shown in Fig. 1, and the mold is in a clamped state. Molten resin is injected from the nozzle of the injection molding machine through the sprue, runner, and gate (not shown), and the product is finished. 3 is molded.

That is, in the process of moving from the mold opening process to the mold closing process until the mold plates 23 and 27 come into close contact and the slide block 42 returns to its original position and comes into close contact with the product 3, the pusher pin 28 is slightly pushed. 29, the ejector plates 31, 32 on which the ejector pin 50 is erected
Slide block 42 to its original position (lower limit position)
It is possible to reliably perform fast reversal before the objects gather at their original positions.

By the way, when moving from the mold closing process (Fig. 1) to the mold opening process (Fig. 2), the ejector plates 31 and 32 are moved relative to the ejector rod of the molding machine as the movable side mold part 21 descends. 7, the sleeve 33 is inserted into the bush 29, the pusher pin 28 is pulled out from the sleeve 33 and the bush 29, and the state shown in FIG. 31, 32 ejector pin 50
It is pushed up by

Effects of the invention As explained above, according to this invention, from the mold opening process to the mold closing process, the sleeve is pushed down by the pusher pin on the fixed side mold part, the ejector pin is quickly returned together with the ejector plate, and the ejector pin is quickly returned. After that, the ejector pin can be inserted into the sleeve, so even if the ejector pin has a fairly large stroke, it can be returned quickly without colliding with the slide block, etc., and there is no risk of damage, making installation easy. It does not take up much space, does not require delicate adjustments, and can be composed of only spheres, cylinders, and cylindrical parts, so it is easy to manufacture, can be made with high precision, and has the excellent effect of improving durability.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the main parts of this invention and showing the state of the mold in the mold closing process, Fig. 2 is a sectional view showing the state of the mold in the mold opening process, and Fig. 3 is a sleeve 4 and 5 are cross-sectional views showing a conventional mold. 20...Fixed side mold part, 21...Movable side mold part, 2
8... pushsha pin, 29... butshiyu, 29b
...Inner diameter large part, 29c...Inner diameter small part, 33...Sleeve, 31, 32...Ejector plate, 3
4...Ball, 35...Small hole, 50...Ejecta pin.

Claims (1)

[Claims for Utility Model Registration] An ejector plate quick-return device for a mold that quickly returns an ejector pin that is attached and fixed to the ejector plate and protrudes into the mold in conjunction with the mold closing operation of the mold, comprising: A sleeve body implanted in the ejector plate, a plurality of balls loosely fitted circumferentially near the tip of this sleeve body, and a position facing the sleeve body on the stationary side mold plate part of the mold. A pusher pin is implanted and inserted into the sleeve body, and the ball is expanded to ensure an insertion path for the pusher pin while the sleeve body is inserted through the movable mold plate portion of the mold. An ejector plate quick return device for a mold, comprising a large inner diameter portion that can move in a direction and a bushing portion having a small inner diameter portion that allows the ball to move in a closing direction to prevent insertion of the pusher pin. .